Speck CandyShell Case on clearance at Target for $10.48 - YMMV
I found the Speck CandyShell case for the Moto X on clearance for $10.48. Both the black and white colors were on clearance.
YMMV on pricing at individual Target stores, but the regular price on this was $34.99. Target clearance prices follow a regular markdown schedule and electronics are normally marked down on Mondays, so if you see it for a higher price, check back the following Monday to see if the price drops. I think the markdown schedule for electronics is 30% off, then 50% off, then 70% off. I don't know if cases would ever get any lower than 70% off, but $10.48 seems like a pretty good price to me.